# A fair die is thrown 20 times. The probability that on the 10th throw, the fourth six appears is

Question : A fair die is thrown 20 times. The probability that on the 10th throw, the fourth six appears is

(A) $20C_{10}\times \dfrac{5^{6}}{6^{20}}$

(B) 120×$\dfrac{5^{7}}{6^{10}}$

(C) 84×$\dfrac{5^{6}}{6^{10}}$

(D) none of these

Answer : option (C)

Solution :

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